A conventional bicycle bottom bracket assembly 80 is shown in FIGS. 10 and 11, and generally includes a bottom bracket 81 with two bearing units 83 connected to two ends thereof and an axle 82 extends through the bottom bracket 81 and is cooperated with the two bearing units 83. Each of the two bearing units 83 includes a bowl 832, a plurality of beads 831 received in the bowl 832 and a locking member 84 which connected to the bowl 832 and guides the movement path of the beads 831. The bowl 832 is engaged with each of two open ends of the bottom bracket 81 and the locking member 84 is threadedly mounted to the axle 82 and connected to the bowl 832 corresponding thereto. Two locking disks are then threadedly mounted to each one of two ends of the axle 82 to position the locking members 84. The accuracy of manufacturing of the parts and the assembling of the bottom bracket assembly decide the rotation of the axle 92 so that, in stead of the manufacturing processes of the parts, the quality of the assembling is crucial for the bottom bracket assembly. The requirements of assembling steps often consume a lot of time when assembling the conventional bottom bracket assembly.
The present invention intends to provide a bicycle bottom bracket assembly which is easily to be assembled and the precision of the assembling can be ensured by special design of the present invention.